THE INFLUENCES OF MATURATION AND WATER IN THE ISOTOPIC COMPOSITIONS OF PYROLYSIS

In order to characterize the influences of maturation and water in the hydrogen isotopic compositions of individual n-alkanes from the pyrolysis,the simulation test of typeⅡsource rock was made by high-pressure autoclave.The analytical results indicate that in the condition of non-hydrous pyrolysis,with the rise of temperature(290～400℃),the individual n-alkanes have the shift toward enriched hydrogen,the difference is over 20‰.But in hydrous pyrolysis,the hydrogen isotopic fractionation is smaller because the lower maturation at the same temperature.Moreover,water has no obvious effect on the hydrogen isotopic compositions of individual n-alkanes in the simulation test.So,the hydrogenisotopic compositions of lipid biomarkers were not obviously influenced by maturation and the hydrogen isotopic exchange during diagenesis.The hydrogen isotopes of lipid biomarkers from source rock can be used to discuss the differences of source rocks and depositional environments and to correlate oil/oil and oil/source.